What is "near-field"

a. In loudspeaker acoustics, referring to a region where the intensity of direct, unreflected sound from the source (such as a loudspeaker) is significantly dominant over any indirect or reflected sound.Brungart Douglas S. and Rabinowitz William R.; "Auditory Localization in the Near-Field"; The Third International Conference on Auditory Display, November 1996 n. 1 (alternative form of near field English) (qualifier: in physical acoustics) 2 (alternative form of near field English) (qualifier: in radio-frequency electromagnetic technology)

In mathematics, a near-field is an algebraic structure similar to a division ring, except that it has only one of the two distributive laws. Alternatively, a near-field is a near-ring in which there is a multiplicative identity, and every non-zero element has a multiplicative inverse.